Ignition system



J. T. FlTZSlMMONS ET AL IGNITION- SYSTEM Filed April 2, 1923 MIT-femfnuenZc7r5 W 7. 76M. q jlfafm 77-1 EZT" #Wy Patented Sept. 6, 1927.

UNITED STATES PATENT orrlcs.

JOHN T. FITZSIMHONS AND HUGH WALLACE, OF DAYTON, OHIO, ASSIGNORS TO GEN-ERAL MOTORS RESEARCH CORPORATION, OF DAYTON,

DELAWARE.

01110, a CORPORATION or IGNITION SYSTEM.

Application filed April 2, 1923. Serial No. 829,398.

The present invention relates to improve- I ments in ignition devicesand more particularly to that type of ignition devices Included inignition systems for internal combustion a or explosion engines, whichsystems include mechanism for interrupting circuits to provide sparkingimpulses.

It is among the objects of the present invention to provide an ignitiondevice wherein the breaker mechanism is kept substantially free fromdisintegration deposits due to sparking, thereby providing clean contacting surfaces in the breaker and facilitating current passagetherethrough. v

Further objects and advantages of the present invention will be apparentfrom the following description, reference being had to the accompanyingdrawings, wherein pre terred forms of the embodiments of the in ventionare clearly shown.

in the drawings:

Fig. 1 is a plan view of the ignition unit; the circuit interruptercontacts being shown in engaged position.

Fig. 2 is an enlarged view similar to Fig. l, the various elements ofthe device being shown in a position where the movable contact has beenmoved, relative to the static-nary contact without disengaging the two.

Fig. 3 is a view similar to Fig. 2 showing the various elements in theposition when tit ontacts have been separated.

t is a side view of the movable eleitu or" the interrupter device.

ig. 55 is a view similar to Fig. 4 talren from the opposite side of theinterrupter device.

Fig. 6 is a diagrammatic view showing the electrical connections of asystem in which this ignition device is used.

A preferred manner of carrying out the objects of the present inventionis to mount one of the contacts of the timer on a ivoted arm and toprovide means actuated by a power driven device, such as a timer cam,for moving the fulcrum of the lever so as to slide the movable contactrelative to the stationary contact, and then separating the contacts.Consequently the contacts after being engaged again will slide, the onerelatively to the other.

Referring to the drawings, the ignition device is shown comprising apair of cooperating contacts including a movable one, designated by thenumeral and a sta-- tionary one designated by the numeral 21. The latteris adjustably supported on a bracket 22,,which, is mounted in butinsulated from the timer cup 23.

The lever carrying one of the contacts, termed the movable contact 20,is designated by the numeral 24. The end of the lever, opposite thecontact element 20, is provided with a circular portion whichencompasses a bushing 26 adapted to form a bearing for the mounting orfulcrum pin 27 of said lever.

The means for moving the fulcrum 27 of the lever 24. before the contacts20 and 2t are separated, includes an operating arm 28, having its oneend pivoted on a stud 22 carried in the timer cup 23, while the otherend of said arm is provided with a rubbing block 30 in operativeconnection with the driving element or cam 31}.

An ear portion 32 is formed in the main body of the operating arm 28between its pivotal point 29 and the rubbing block 80. The fulcrum pin2'?" which rotatably carries the lever 24; is supported by this carportion 32 and the operating arm 28. A. spring 38 having its one endsecured to the termlnal post 34' passes around the pivotal point of thearm 28 and has its opposite end anchored to the contact lever 24. i v

This spring tends to hold the contact element 20 in engagement with thestationary contact 21 while at the same time pressure is exerted uponthe lever 24 which as has been mentioned heretofore, is mounted on andcarried by the arm 28, thus this pressure upon the lever 24 will betransmitted to the operating arm 28 to cause said arm or rather itsrubbing bloclr 30 to be held in operative connection with the drivingelement or cam 31.

Assuming that the various elements of this device are in a position asis shown in Fi 1, where the rubbing block 30 is shown ri ing on the flatsurface of the cam element 31 nearest to its axis, and the contactelement 20 being in aligned position and in engagement with thestationary contact 21, it will be seen that no portion of the arm 28 nor1 ports the arm 24.

Now assuming that the ignition device has been operated to causerotation of the cam 31 in a clockwise dire'ction, to a position as isshown in Fig. 2, it may be clearly seen that the rubbing block 30 hasmoved along the surface of the cam 31, approaching its highest point onsaid cam but not yet reaching same thus having rotated the lever 28about its fulcrum point 29 in a counterclockwise direction. Thisrotation of the arm '28 has also rotated the fulcrum point 27 of thelever 24 radially relative to the fulcrum point 29 of the lever 28. Theend of the rubbing block 30 opposite to that en aging with the cam 31has now also een brought into engagement with the arm 24. The action ofthe spring is to hold the contact element 20 in engagement with thestationary contact element 21 and no force having been brought intoaffect to push or operate the arm 28 to move'the contact 20 out ofengagement with its cooperating contact 21, the aforementioned rotationof the pivoted point 27 of arm 24 radially to the pivot point 29 of arm28 has therefore caused a sliding movement of the contact element 20relative to the contact element 21 without disengaging the same, movingthe contact 20 out of alignment with this contact element 21 as is shownin the Fig. 2. This rubbing movement between the two contact elementscreates friction therebetween which tends to keep the faces of saidcontact elements polished thus eliminatin disintegration deposits on thefaces thereo Upon further movement of the cam element 31 to cause therubbing block 30 to ride upon the highest point of the cam as is shownin Fig. 3, the end of the rubbing block 30 en aging with the contact arm24 will rotate the contact arm 24 with the arm 28 as a unit around thepivot point 29, thus moving the contact point 20 out of engagement withthe stationary contact element 21. It will be seen that when the rubbingblock 30 again rides off the highest point of the cam 31, the contactelement 20 will first be moved to engage with the stationary contactelement as is shown in the Fig 2 and further rotation of the cam 31 willcause the contact element 20 to be moved on the contact element 21 witha sliding motion into aligned position as 15 shown In the Fig. 1.

Current flowing through the primary cir-- cuit including the primarycoil 40 and the contacts 20 and 21 being intermittently broken by thesecontacts will tend to cause an arcing which causes the surfaces of thecontact points to become pitted thereby tending to affect the passing ofcurrent across these points. By the use of the present invention, thispitting of the contact surfaces or rather accumulation of contactdisintegration material u on their surfaces will be substantiallyeliminated inasmuch as the contacts previous to being broken andimmediately after again brought together will be slid one on the otherthereby tending to rub off any such accumulation as might take place andfacilitating the passing of current therethrough.

While the form of embodiment of this invention as herein disclosed,constitutes a preferred form, it is to be understood that other formsmight be adopted, all coming within the scopeof the claim which follows.

What we claim is as follows:

In an ignition device for internal combustion engines and in combinationwith an engine driven cam, an operating arm, one end of which ispivotally su ported from a fixed support; a rubbing b ock carried by thefree end of said arm, and which is adapted to engage the cam aforesaid;a contact carrying lever overlying and extending beyond the extremity ofsaid operating arm, and which lever is pivotally connected with saidoperating arm at a point offset from a line joining t e pivotal sup ortof said arm and the extremlt of sai rubbing block which engages sai cam;afixed contact; and a movable contact carried by the free end of saidcontact carrying lever and adapted to engage said fixed contact; saidrubbing block being arranged substantially at right angles to saidoperating arm, and the end thereof remote from said cam being adapted toengage said contact carrying lever to separate said contacts.

In testimony whereof we hereto affix our signatures.

JOHN T. FITZSIMMONS. HUGH WALLACE.

